In a rotary electric machine such as an electric motor, components configuring the rotary electric machine, for example, a coil experiences a large increase in temperature by operation, which may cause insulation failure and fire damage. Therefore, a temperature sensor is attached to the coil to detect the temperature of the coil.
Patent Literature 1 proposes, in order to stably and accurately measure the temperature of the coil for a long time, a bracket that is fixed to a casing of the rotary electric machine, a metallic elastic arm that extends from the bracket toward an outside surface of a coil end, and a resin thermistor holder that is attached to a front end of the elastic arm to hold a thermistor. The thermistor is brought into contact with the outside surface of the coil end to detect the temperature of the coil end.
In the temperature sensor proposed by Patent Literature 1, it is possible to stably press a temperature detecting site of the thermistor against the outside surface of the coil end for a long time because the elastic arm is made of a metal and the elastic force thereof is not deteriorated with age.
In addition, the elastic arm is formed through insert molding such that a resin layer of the thermistor holder is interposed between the elastic arm and the thermistor. Therefore, heat transmitted through the arm of the bracket is insulated by the resin layer of the thermistor holder, and is not transmitted from the front end of the arm to the thermistor, which makes it possible to prevent the thermistor from being affected by temperature of a casing.